Bears are emerging from hibernation in the Greater Yellowstone Area, and rangers are advising hikers, skiers and snowshoers to stay in groups of three of more, to make noise on the trail and carry bear spray.

On March 12, 2012 Yellowstone National Park employees observed a grizzly bear in the north central portion of the park. Fresh tracks were also spotted during the same time frame in the Old Faithful area.

There have also been several reports of grizzly bear activity in the Shoshone National Forest east of the park's boundary during the previous week.

Bears begin looking for food soon after they emerge from their dens, rangers said. They are attracted to elk and bison that have died during the winter. Carcasses are an important enough food source that bears will sometimes react aggressively when surprised while feeding on them.

Two fatal bear attacks marred last year's summer season at Yellowstone National Park.

Park rangers on Aug. 29, 2011 identified John Wallace, 59, from Chassell, Mich. as the victim of a grizzly attack while he was hiking along the Mary Mountain Trail.

A Board of Review report issued by the Interagency Grizzly Bear Committee on March 5, 2012 confirmed that Wallace died of traumatic injuries from a grizzly bear attack. The report includes details regarding the investigation and autopsy.

Wallace's death followed a similar grizzly attack in early July 2011 that claimed the life of Brian Matayoshi, 57, from Torrance, Calif.

Matayoshi and his wife, Marylyn, were hiking Wednesday morning, July 6, n the Wapiti Lake Trail, located off the South Rim Drive, south of Canyon Village and east of the park's Grand Loop Road.

Rangers said the couple was hiking west back toward their vehicle just before the attack.

There had only been seven fatal attacks recorded in history of Yellowstone prior to 2011.

Yellowstone also recently produced a new video on the proper use of bear spray, which will soon be available to view on the park Web site, and interpretive park rangers will be conducting bear spray demonstrations at scheduled times throughout the park this summer season.

The park also implements seasonal bear management areas closures to reduce encounters between bears and humans in areas where elk and bison carcasses are in high density. A listing of these closures can be found at www.nps.gov/yell/parkmgmt/bearclosures.htm.

Yellowstone regulations require visitors to stay 100 yards from black and grizzly bears at all times. The best defense is to stay a safe distance from bears and use binoculars, a telescope or telephoto lens to get a closer look.

All visitors traveling out of developed areas should stay in groups of three or more, make noise on the trail, keep an eye out for bears and carry bear spray. Bear spray has proven to be a good last line of defense, if kept handy and used according to directions when a bear is approaching within 30 to 40 feet.

While firearms are allowed in the park, the discharge of a firearm is a violation of park regulations. Even the park's law enforcement rangers who carry firearms on duty rely on bear spray, rather than their weapons, as the most effective means to deal with a bear encounter.

Visitors are also reminded to keep food, garbage, barbecue grills and other attractants stored in hard-sided vehicles or bear-proof food storage boxes. This helps keep bears from becoming conditioned to human foods, and helps keep park visitors and their property safe.

Bear sightings should be reported to the nearest visitor center or ranger station as soon as possible.

Visit the park's Website at www.nps.gov/yell for information on visiting Yellowstone.